Machine for making concrete slabs or plates.



C. L. NORTON. MACHINE FOR MAKING CONCRETE SLABS 0R PLATES.

APPLICATION FILED IULY15. 1914.

1,140,702. Patented May 25, 1915.

3 SHEETSSHEET l.

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atzfys C. L. NORTON.

MACHINE'FOR MAKING CONCRET ESLABS 0R PLATES.

APPLICATION FILED JULY 15. 1914.

1,140,702. Patented May 25,1915.

witnesses Inventor.

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C.'L. NORTON.

MACHINE FOR MAKING CONCRETE SLABS OR PLATES.

APPLICATION FILED JULY 15, 1914.

1,140,702. Patented May 25, 1915.

3 SHEETS-SHEET 3.

Vim W b0. QQQ- 3 9' A 2%; A 6%.. atgy CHARLES L. NORTON, OF HUDSON, NEWHAMPSHIRE, ASSIGNOR TO ASBESTOS SHINGLE COMPANY, OF NASHUA, NEWHAMPSHIRE, A CORPORATION OF NEW YORK.

Specification of Letters Patent.

Patented May 25, 1915.

Application filed July '15, 1914. Serial No. 851,223.

To all whom it may concern Be it known that I, CHARLES L. NORTON, acitizen of the United States, and resident of Hudson, in the county ofHillsboro and State of New Hampshire, have invented new and usefulImprovements in Machines for Making Concrete Slabs or Plates, of whichthe following is a specification.

My invention relates to the art of continuous production of concreteslabs or plates, such as typified by the machine shown and described inUnited States Patent No. 979,548, dated December 27, 1910, and has forits object the improvement of the operation and the product of suchmachines, in respect particularly to uniformity and regularity.

Especially, the object is toproduce finished concrete plates or slabs ofuniform thickness, density and strength.

Since the instruments by which the materials composing the concrete arecompressed are, of practical necessity, unvarying in their action afterhaving been once adjusted for a given course of operation, theseimprovements are addressed to the regulation of the supply of materialwhich is afterward conveyed to thecompressing factors.

An example of the materials to be treated is described in the abovementioned United States patent. As it is fed to the slab or platemakingmachine in a dry, comminuted state, it is capable of flowing insome measure like a liquid, provided proper conditions are preserved.And, like a liquid, this material, if made to assume columnarproportions, exertsstatic pressure in all directions, somewhat like acolumn of liquid, although, unlike a liquid, it is compacted orcompressed in proportion to the amount of pressure sustained. Theinvention herein described thus presents two aspects, one that of amethod or process, characterized by the continuous feeding of comminuteddry material to a conveyer under a substantially constant static, selfproduced pressure, or, under the static pressure, self produced in thematerial by the maintenance of a substantially constant columnar headover the oint of delivery to the conveyer, the other that of a machineby which the above characterized process or method may be carried on.Claims for the method are presented in an application for United 'StatesLetters ,machine; Fig. 3 is a longitudinal central vertical section ofthe hopper-end of the machine; and Fig. 4 is a vertical cross section ofthe machine at the line 44 of Fig. 3.

Referring to Fig. 1 (and also to said United States Patent No. 979,548for a description of a machine of the type under consideration) thenumeral lrepresents a belt conveyer which may be a single endless belt,(or a pair of conveyers placed end to 'end, as shown in the said patent)driven at constant speedin the direction of the arrows drawn adjacent tosaid conveyer. This conveyer 1 will be referred to as the main conveyer,since another conveyer enters into the organization of the machine. 2,2, and 3, 3, are the press rolls, which rotate in the directionindicated by arrows; 4 is a rotating cutter which grooves the materialM, dividing it into separate plates or slabs; 5 is a water supply devicewhich wets the material after it has received a preliminary drypressingby the press rolls 2, 2; 6 is the de livery roll, 7 a leveling wormwhich reduces the depth of the material which proceeds from the hopperA; 8 is a rotating brush, which completes the work of reducing thethickness of material to a uniform dimension; 9 is a side-trimmer, whichtrims the edge of the layer of material so as to deliver a layer ofuniform width to the press rolls, and 10 is a table or support overwhich the belt-conveyer, or main convever, 1, passes. There is, ofcourse, a side-trimmer 9 on each side of the main conveyer. side of themain conveyer 1 there is a rotarv wiper or brush L, which serves toclean the surface of the conveyer and to remove from it part of themoisture remaining after the plates S have been removed from the end ofthe conveyer when it passes over the delive roll 6.

It will be observed that the machine above briefly described differsfrom that which is the subject of United States Patent No.

On the under- 979,548, in .that the main conveyer is here shown as asingle. endless belt, whereas in 7 the said patent the machine isspecifically vBIS characterized by two belt conveyers, placed end toend, with a gap between, which is' spanned by a bridge, over which the,first belt pushes'the layer of dry-pressed material tothe second belt,which is wet. While the machine of that patent has been successfullyemployed in the commercial manufacture of concrete plates, its eflicientbehavior was conditioned on sundry nice adjustments of machine andmateria s, particularly in relation to the transit of material over thestationary bridge between the belts. The machine herein depicted anddescribed comprises sundr inventions and improvements herein claimed,and these improvements, which make possible the employment of a singleendless main conveyer, and obviate.

the necessity of the stationary bridge aforesaid, with its concomitantdifiiculties, are the subject of another application, filed concurrentlyherewith, Serial No. 851,858.

Passing now to the subject'matter with which the present specificationis more inti- -mately concerned,there is mounted over the receiving endof the main conveyer a hopper A, having an open bottom close to thesurface of the main conveyer, and a lateral gateway A, opening in thedirection of the travel, of the conveyer surface. In its preferred form,the hopper A is a cylindrical stand-pipe, which has, therefore, circularcross section, well adapted to the uniform distribution of staticpressure through the mobile material contained in it. Though it is tocontain solids only, this hopper A is essentially a pressure tank. Thetop of the hopper'A is also open, and supply pipes E and G delivercomminuted material into the top of the hopper. Within the hopper A,there is a shaft J (Fig. 3) rotatably mounted, and armed with crossed,flat paddle blades K, K, which continually stir the material and preventit from caking or arching, in other words, by agitating the material theaddles K maintain it in a quasi fluid con ition, conducive to theproduction of, fluid pressure throughout its mass, a pressure which ismaintained specifically uniform all over the bottom of the hopper A, bythe following means.

Since the comminuted solid material is made to behave practically as ifit were a fluid, the static pressure in the columnv within the hopper Aincreases in direct proportion to the depth of the column. Inorder tomaintain the desired uniform static pressure at the bottom of the hopperA, where the material is delivered to the main con veyer 1, the columnof material is kept at constant height. The preferred specific mode ofmaintaining uniform and constant pressure at the bottom of the hopper isto produce a continual overflow from the open top of the? hopper. Tothis end, the followmg arrangement of apparatusis found suitab e. Anendless belt B,termed the return conveyer, ismounted on rolls 6 and b,be-

.low the' main conveyer, so as to catch the surplus material, purposelysupplied and pugposely removed b the vworm 7, brush 8,: a an Meanwhile afresh su ply of material is in-. troduced by means 0 appropriateapparatus, such as the chain or ucket hoist and pipe E. The returnsupply andfresh sup-- ply to ether continuously introduce into the top 0the hopper A more material than emerges from the bottom of the hopper,so that there is a continual spill from the top of the hopper, into thelip-chute F, which delivers the spill to the return conveyer B. Theagitating paddles K preserve the column of material in the hopper A in amobile condition, sothat as it descends, the material becomesprogressively more and more compacted, sustaining therefore an initialconsolidating pressure, constant in degree and uniform in distribution,at the point of delivery to the main conve er 1. Furthermore, in orderto have the and or layer of material which is to be subjected to thesucceeding stages of compression, uniform in transverse section as wellvas uniform in density, the lateral gateway A is so proportioned that itdelivers a band of material substantially thicker and wider than thedesired final proportions. Part of this designedly supplied surplus isscraped ofiby the right and left pitched worm 7 which pushes thematerial sidewise off the edges of the main conveyer 1. Then the brush8, which is a cylinder armed with short wooden or metal splints, levelsoff the top surface of material still more, giving it a finishing cut.The predetermined thickness of material being thus obtained, the sidescrapers throwing this surplus oil, to be caught by the return conveyerB. Then the material is compressed further by the dry press rolls 2, 2,is then wetted with water falling from the dampener 5', transverselygrooved by the rotating lmife-frame 4, wet pressed by the press rolls 3,3, and finally removed, in individual slabs, each of which is slid on toa' steel plate as it comes off the main conveyer 1.

he details of mechanism are illustrated in F1 2, 3 and 4, and require nofurther exten ed explanation, in view of the foregoing.

What I-claim, and desire to secure by 5 Letters Patent, is: I

1. In a machine of the character described, the combination of a conveer, a tubular hopper with a delivery ori ce at one side at 1ts lower endand a spill open- 10 ing at a point above its lower end, the conveyerconstituting the bottom closure of the hopper, and means to feed drymaterial to the hopper, in excess of the material-removing capacity atsaid lateral orifice at the 15 lower end of the hopper.

2. In a machine of the. character described, the combination of ammo er,a tubular hopper with a delivery 0 ee at one side at its lower end and aill opening at a point above its lower en the con- 20 veyer constitutingthe bottom closure of the hopper, means to feed dry material to thehopper, in execs of the material-removing capacity at said lateralorifice at the lower end of the hopper, and means to 26 agitate thematerial in the hopper.

Signed by me at Boston, Mmachusetts, this thirteenth da of Jul 1914.

. (ll- ABLE L. NORTON. Witnesses:

RonnR'r CUsnMAN, Cums D. Woonnmmm

